Pharmacokinetics of prednisolone transfer to breast milk

Prednisolone transfer to breast milk was studied in three nursing women who required oral steroid therapy for asthma. Each patient received a 50 mg intravenous dose of prednisolone phosphate, and blood and breast milk were sampled for 6 hours. Concentrations of prednisolone in milk declined more rapidly than in serum but were similar to expected unbound serum concentrations, suggesting that exchange between unbound prednisolone in serum and breast milk is relatively rapid and bidirectional. Because an average of 0.025% (range, 0.010% to 0.049%) of the prednisolone dose was recovered in milk, prednisolone transfer to breast milk does not appear to pose a clinically significant risk to nursing infants. Clinical Pharmacology and Therapeutics (1993) 53, 324–328; doi: